Composite yarn consolidation device

ABSTRACT

There is provided an apparatus, and method, of consolidating yarns. The apparatus has a surface configuration conforming to the general equation y ekx wherein x is the axial distance from a point on the roller axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve and is smaller than 0, and the method passes a yarn to be consolidated over such an apparatus. The method and apparatus provide an improved technique of consolidating yarns compared to other proposals in the art.

United States Patent Boisvert 1 July 15, 1975 COMPOSITE YARN CONSOLHDATiON 3,094,834 6/1963 Deelcy et a1 57/774 x DEVICE 3,559,391 2/1971 R108 57/77.4

3,581,487 6/1971 Loomes et a1. 57/34 R [75] Inventor: Jean Boisvert, Ste-Rose, Canada 1 73] Assignee: The Bobtex Corporation Limited, Primary E.\aminerDonald E. Watkins Montreal, Canada Attorney, Agent, or Firm-Robert .1. Schaap [22] Filed: June 17, 1974 Appl. No.: 480,318

Foreign Application Priority Data July 3, 1973 Canada 175433 US. Cl 57/77.4; 57/156 Int. Cl. D0lh 7/92; D02g 1/02 Field of Search 57/34 R, 77.3, 77.4, 156

References Cited UNITED STATES PATENTS 11/1946 Bcllezza 57/77.4 3/1952 Brown 57/77.4

[57] ABSTRACT There is provided an apparatus, and method, of consolidating yarns. The apparatus has a surface configuration conforming to the general equation y e' wherein x is the axial distance from a point on the roller axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve and is smaller than 0, and the method passes a yarn to be consolidated over such an apparatus. The method and apparatus provide an improved technique of consolidating yarns compared to other proposals in the art.

14 Claims, 4 Drawing Figures COMPOSITE YARN CONSOLIDATION DEVICE This invention relates to a method and apparatus.

More particularly, this invention relates to a method and apparatus for consolidating fibers to a matrix of molten polymer.

The production of yarns from fibers solidified onto a matrix of molten polymer is known in the art and reference may be had to, for example, Canadian Pat. No. 847,099 Universal Open-End Spinning Method of Multicomponent Yarns Production, Canadian Pat. No. 880,988 Composite Fibrid Yarns and Method of Manufacture, and like patents, both issued to Emilian Bobkowicz and Andrew J. Bobkowicz on July 21, 1970 and Sept. 14, 1971 respectively.

One of the steps in the production of such yarn materials, following the formation of the fiber coated matrix, involves the consolidation of this material to form a composite structure. Generally speaking, it is known in the prior art that fiber consolidation on a matrix of molten polymer can be achieved by passing the composite structure over a driven surface having a circumferential speed component of direction vis-a-vis the composite structure direction. Many different types of devices have been proposed for this purpose; however, in general it can be said that with the known methods and devices, various obstacles have arisen which have always limited their applicability. Thus, for example, problems have arisen with prior art methods and devices which have limited the simplification in the speeding up of production and reduction in cost, which in turn, are the problems related to the stability and power consumption. Consequently, the prior art methods are either costly or do not permit the attainment of the high speeds desired in such yarn consolidating techniques. A further problem which has arisen is that prior art devices, even if capable of attaining high speeds, have the characteristic of wearing out very fast and as a consequence, require replacement thus adding to the cost of the operation and in addition, down time on amachine.

.In accordance with this invention, and specifically in accordance with one embodiment of the apparatus thereof, applicant has developed an improved apparatus which overcomes the problems of the prior art and which consolidating apparatus comprises a rotatable spindle, preferably freely rotatable, the spindle being characterized by having a surface configuration which is defined by the general equation y kx wherein e is the natural logarithm base;

x is the axial distance from a point on the roller axis;

wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve and is samller than In the above structure, the concave surface is engageable by a fiber coated matrix or composite structure over which the composite structure is adapted to pass in a defined path; to this end, preferably the concave surface of the spindle has a first fiber receiving area in an initial fiber contacting area for the composite structure which has a relatively high coefficient of friction with respect to the composite yarn structure,with the concave spindle surface further having a consolidating area in the defined path which is characterized as having a high degree of coefficient of friction with respect to the consolidated yarn structure and further which is characterized as being formed of a hard-wearing material.

In accordance with the method of the present invention, the method includes in one embodiment, the steps of providing a source of a composite yarn structure of a fiber coated matrix to be treated to form a consolidated yarn structure, and passing the composite yarn structure in contact with a spindle having a concave surface in which the composite yarn structure is passed through a defined path on the concave structure from an initial receiving area on the spindle surface to a discharge point thereon to thereby form the consolidated yarn structure, and in which the concave surface conforms to the equation I y ka:

wherein x is the axial distance frorna point on the roller axis; wherein y is the circumferencelocation from the axis from a given x value; and whereinklis a constant defining the curve and is smaller than 0.

In carrying out the above method, preferably the composite yarn structure is initially passed, for at least a portion of a convoluted path, in contact with the concave surface having a higher degree of coefficient of friction with respect to the composite structure and thereafter subsequently passed to a further convoluted path in communication with the first-mentioned convoluted path while in contact with a portion of the concave surface having a higher degree of coefficient of friction with respect to the resulting consolidated structure, the last-mentioned convoluted path having a diameter less than the diameter of the first-mentioned convoluted. path, whereafter the consolidated yarn structure is subsequently discharged from said lastmentioned convoluted path.

In carrying out the method of the present invention and in utilizing the device thereof, the composite yarn structures to be consolidated are preferably those taught in the abovenoted Canadian patents and comprise fiber coated matrixes of thermoplastic polymers. The above patents, and others to the same inventors, clearly set forth the types of materials from which the composite structures may be formed and the various types of method and apparatus that may be used for their formation, and accordingly, those skilled in the art may have reference to those teachings for use in the various types of composite structures that may be treated in accordance with the method and apparatus of the present invention.

In the apparatus of the present invention, the spindle device according to one embodiment and as outlined above, may be characterized as having an initial fiber receiving area or portion which has a high degree of coefficient of friction relative to the composite structure. To this end, the spindle may be formed of, or at least have the surface portion adapted to be in contact with the-composite structure in the initial portion of the defined path, of a suitable material such as, for example, urethane, rubber, ceramic, steel, chromium and other like materials. The texture and grain of this surface can also vary to adapt in an optimum preferred manner to the composite yarn being processed. Examples of such texture variations can be high gloss smooth finish,

matte surface, knurled su'rfac'e, random groove pattern, or directed groove patterng for' example parallel to one yarn form to aid in one apparatus-yarn interaction to achieve an optimum consolidation effect.

The second portion of the defined path likewise is characterized as having a high coefficient of friction with respect to the consolidated yarn structure and to this end, the balance of the spindle, or at least the surface thereof, is formed of a material such as reinforced urethane or epoxy, hard rubber, ceramics, etc.

As will be appreciated-by those skilled in this art, the coefficient of friction of the composite yarn structure, and of the consolidated yarn structure, will vary depending on the type of materials forming such structures. Thus, from the above materials, an appropriate one, or mixtures, will be chosen to have the desired coefficient of friction having regard to the specific type of yarn structure to be processed. Most preferably, the materials which are selected for this purpose are those which are characterized as forming a hard-wearing sursurface generally the same as the envelope of a tridimensional damped motion which may be defined by the equation y kr wherein x is the axial distance from a point on the roller axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve. By providing a surface having thisconfiguration, for the defined path for the composite yarn structure to form the consolidated yarn structure,

optimum running stability is attained. This, the path of the composite Thus, structure on the spindle will be controlled by the back tension applied to the yarn so that whenever a variation on this back tension occurs, the resulting reaction will generate a displacement on the roller'surface. In order to provide the stable system of the present invention, this displacement must be damped along the surface of the spindle. The surface configuration is then controlled by the following differential equation wherein T is the tension.

The general solution for the above equation is:

y Ce

wherein x is the axial distance from a point on the roller axis; y is the circumference location from the axis'from a given at value; and c and are constants defining the curve.

As will be evident, three possible solutions may be provided wherein In the case where k is greater than 0, it will be appreciatedthat the roller will react as an amplifier and the tension variation will increase; while on the other hand, if k equals 0, then y equals c which defines a plain cylindrical configuration. Conversely, when k is less than 0, then thetension vibrations maybe damped by the surface curvature variation which thus gives rise to the advantageous features of the present invention. Thus, by providing a consolidated device havinga surface configuration corresponding to the formula and wherein x, y and k'areabove-defined, .then optimum running stability ,forthe composite structure is obtained. a H v a In passing the composite yarn structure through the defined path over the concave surface of the spindle having defined axial and circumferentialcomponents of direction in such a manner that the composite structure drives the freely rotatable roller, consolidation of the composite structure is achieved over the whole external surface of the matrix of the molten polymer as it is being treated in accordance with the method of the present invention. In other words, by means of friction, the circumferential component of direction of the spindle surface over the fiber coated matrix generates a circumfe'rential component of direction of the fiber coated matrix allowing a uniform circumferential consolidation of the composite structure. The circumferential direction speed component of the spindle surface over the fiber coated matrix is controlled by the spindle surface rotational speed, which in turn, is controlled by 'the running composite'structure speed. Good consolidation of the composite yarn structures have been obtained when the circumferential direction speed component of the spindle surface over the fiber coated matrix in the initial fiber receiving area of the spindle surface with the fiber coated matrix was over at least about two times the running composite structure speed.

The device of the present invention may be mounted to any suitable substrate surface in a freely rotatable .manner byconventional procedures; to this end, suitably the device may be journalled on a bearing structure e.g., in anti-friction bearing and preferablyis mounted in a cantilever manner. However, if desired, the device of the present invention may be driven by any suitable means rather than relying on the passage of the yarn through the defined path in communication with the concave spindle surface to providethe rotational power; to this end, the device of the present invention may be modified to include appropriate power shafts to rotate the same within the desired rotational speed range. Still further, if desired, the spindle device of the present invention may include means to electrically charge the' surface thereof for the purpose of attracting fibers, according to conventional techniques known to those skilled'in this art. In a like manner, the spindle device may also be modified to provide a plurality of 'apertures'therein in communication with the surface of the spindle, with the spindle being mounted and connected in operative relationship to suitable vacuum generating'means to provide a suction at the surface of the spindle device in operative relationship to the defined path of travel of the composite yarn struc ture. To this end, typically the apertures in the spindle device will extend inwardly from the surface thereof in communication with a hollow conduit internally located in the spindle and in communication with the apertures. The conduit may be connected in any desired manner to the source of vacuum.

From the above description, it will be seen that the present invention provides a novel, simple and expedient manner of consolidating composite yarns, which overcomes the disadvantages of the prior art. The device and method of the present invention permit high operating speeds and a very stable production of consolidated yarns; further, the apparatus is very inexpensive to manufacture and maintain.

. Consolidation of yarns using the method and apparatus of the present invention can be carried out with various, types and sizes of yarns under a wide range of speeds.

Having thus generally described the invention, reference will now be made to the following drawings illustrating preferred embodiments and in which:

FIG. 1 is a schematic view of a portion of a fiber manufacturing apparatus including the consolidating device of the present invention;

FIG. 2 is a schematic perspective view of the consolidating device of the present invention;

FIG. 3 is a side elevational view of the device of FIG. 2; and

FIG. 4 is an enlarged side elevational view of a portion of the device of FIGS. 2 and 3.

Referring now in greater detail to the drawings, and with reference to FIG. I initially, the consolidating device of the present invention may be used in a typical yarn manufacturing process and apparatus, in which a composite yarn structure to be consolidated is passed from a prior manufacturing operation, as for example, disclosed in Canadian Pat. No. 880,988 issued Sept. 14, 1971 to E. Bobkowicz and A. J Bobkowicz and entitled Composite Fibrid Yarns and Method of Manufacture; the composite yam structure indicated generally by reference numeral passing between spaced apart rotatable rollers 12 and 14, suitably joumalled on shafts 16, to the consolidating device indicated generally by reference numeral 20. Thereafter, the resulting consolidated yarn indicated generally by reference numeral 18 may be subsequently processed according to conventional practices; the yarn passing over a pair of wind-up rollers 22 and 24 suitably journalled on shafts 26 or alternately, being fed to subsequent processing steps following the arrow 28.

In accordance with this invention, the consolidating device comprises a spindle portion indicated generally by reference numeral 30, which is freely rotatable on and mounted by a journalling shaft 32. This shaft 32 may be mounted by any suitable means, such as a bearing (not shown) to a rigid surface (not shown); preferably the freely rotatable spindle is mounted in a cantilever manner on the shaft 32. i

The spindle 30, embodying the features of the present invention, includes a generally concave surface 34 extending from a wider base portion in the initial fiber receiving path area of the spindle, and extending through a narrower consolidated fiber discharge portion or the terminal portion of the defined path over which the fiber is adapted to travel, as set forth hereinafter in greater detail.

More particularly, the consolidating device of the present invention is so constructed so as to provide a defined path which has a first or initial portion of that path indicated generally by reference numeral 36 adapted to receive a fiber coated matrix forming the composite structure 10, for subsequent consolidation of the same on the device 20 and which area 36 of the spindle forms the wider base portion of the spindle adjacent the base 36a. This area 36 of the spindle 20 is characterized by having a relatively high coefficient of friction with respect to the composite yarn structure 10 and as such, may be made of any suitable material fulfilling these requirements such material being for example, urethane rubbers, or others such as those mentioned above. I

Thereafter, the composite yarn structurelo'is consolidated over the balance of the spindle surface in that area designated by reference numeral 40 following the defined path for the yarn, with the area'40 of the surface 34 being formed of a suitable hard-wearing material characterized by having a high degree of coefficient of friction relative to the consolidated 5/; "structure 18' The consolidated yarn structure, at the" terminal end of its travel on the surface 34 of the spindle 20, functions to drive or rotate the spindle 20 in the area indicated generally by reference numeral 7, whereafter the wherein x is the axial distance from a point on the roller axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve and is smaller than 0. As explained hereinbefore, it has been found in accordance with this invention that such a surface provides the optimum properties for the consolidation of composite yarn structures, and provides the advantages of the present invention. In this respect, thedegree of consolidation can be controlled by increasing or decreasing the tension of the composite yarn prior to engagement of the same to the concave surface 34; alternately, by displacing the initial contact point, as indicated generally by reference numeral 50 (FIG. 3) to a further point within the area 36 having a smaller circumference than the point 50 or still further, by varying both of these factors.

In accordance with the process of the present invention, and utilizing the above described apparatus, and with particular reference to FIG. 4, the latter figure illustrates the force balance on the surface 34 of the spindle 20 for achieving stability during the process.

'Thus, a composite yarn structure to be consolidated is passed over the spindle 20 through the initial area 36 of. the defined path for the yarn and, under a steady state, the yarn is held in place by the tension which is indicated by tension arrows 42 and 44. If, during the processing conditions, the tension on the composite yarn structure 18 is varied for any reason, it will be seen that as a result, the tension may be corrected by a displacement controlled by the tension 44. Thus, if the tension indicated by tension arrow 42 is decreased, the displacement of the yarn will be in a direction to shift the composite yarn structure 10 from a radius such as that illustrated in FIG. 4 by reference numeral 46 to a smaller radius such as that indicated by arrow 48, with respect to the axis XX'of the spindle so that as a consequence, the rotational speed of the spindle 20 will increase and will inherently re-balance the force balance between the lines of tension indicated by arrows 42 and 44.

It will be understood that various modifications can be made to the above described embodiments without departing from the spirit and scope of the invention as described herein.

I Claim:

1. A consolidating apparatus comprising a rotatable spindle, said spindle having a surface configuration conforming to the general equation y wherein at is the axial distance from a point on the spindle axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve and is smaller than 0.

2. An apparatus, as defined in claim 1, wherein said spindle has a concave surface engageable by a composite yarn structure over which the composite structure is adapted to pass in a defined path, said concave surface of the spindle having a first fiber receiving area in an initial fiber'contacting area for the composite structure which'has a relatively high coefficient of friction with respect to the composite structure, said concave spindle surface further having a consolidating area in the defined path of a high degree of coefficient of friction with respect to the consolidated yarn structure.

3. An apparatus, as defined in claim 1, wherein said spindle is a freely rotatable spindle.

4. An apparatus, as defined in claim 1, wherein said spindle is a driven spindle.

5. An apparatus, as defined in claim 1, wherein said spindle includes suction means adapted to create a suction on the surface thereof.

6. An apparatus, as defined in claim 1, wherein said spindle surface is electrically chargeable for attracting fibers.

7. A method of consolidating a composite yarn structure to form a consolidated yarn structure comprising providing a source of a composite yam structure, passing the composite yarn structure in contact with a spindle having a concave surface in which the composite yarn structure is passed through a defined path on the concave structure from an initial receiving area on the spindle surface to a discharge point thereon to thereby form a consolidated yarn structure, said composite yarn structure being brought into contact with a concave surface conforming to the equation y kz wherein at is the axial distance from a point on the spindle axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve of the surface and is smaller than 0.

8. A method as defined in claim 7, wherein the source of composite yarn structure is passed for at least a portion of a convoluted path while in contact with the concave surface of said spindle which has a higher degree of coefficient of friction with respect to the composite structure and thereafter the yarn structure is passed through a further convoluted path in communication with the first-mentioned convoluted path while in contact with the concave surface of the spindle and which has a higher degree of coefficient of friction with respect to the resulting consolidated structure, the lastmentioned convoluted path having a diameter less than the diameter of the first-mentioned convoluted path, following which the resulting consolidated yarn structure is discharged from said last-mentioned convoluted path.

9. A method, as defined in claim 7, wherein the passing of the yarn structure in engagement with the spindle drives the spindle.

10. A method, as defined in claim 7, which includes the step of positively driving the spindle.

1 1. A method, as defined in claim 7, wherein the yarn structure is subjected to a suction through at leasta portion of said defined path.

12. A method, as defined in claim 7, which includes the step of generating an electrical charge on the surface of said spindle.

13. A method of consolidating a composite yarn structure to form a consolidated yarn structure comprising providing a source of a composite yarn structure, passing the composite yarn structure in contact with a spindle having a concave surface in which the composite yarn structure is passed through a defined path on the concave surface from an initial receiving area on the spindle surface to a discharge point thereon to thereby form a consolidated yarn structure, said composite yarn structure being brought into contact with a concave surface conforming to the equation:

wherein x is the axial distance from a point on the central axis of the spindle defining a distance along the central axis from said point to one end of said axis; wherein y is the circumference location from any location on the central axis to the surface of said spindle for any given x value; and wherein K is a constant defining the curve of the surface and is smaller than 0.

14. A consolidating apparatus comprising a rotatable spindle, said spindle having a surface configuration conforming to the general equation wherein x is the axial distance from a point on the central axis of the spindle defining a distance along the central axis from said point to one end of said axis; wherein y is the circumference location from the axis from any location on the central axis to the surface of said spindle on any given x value; and

wherein k is a constant defining the curve and is, smaller than 0. 

1. A consolidating apparatus comprising a rotatable spindle, said spindle having a surface configuration conforming to the general equation y ekx wherein x is the axial distance from a point on the spindle axis; wherein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve and is smaller than
 0. 2. An apparatus, as defined in claim 1, wherein said spindle has a concave surface engageable by a composite yarn structure over which the composite structure is adapted to pass in a defined path, said concave surface of the spindle having a first fiber receiving area in an initial fiber contacting area for the composite structure which has a relatively high coefficient of friction with respect to the composite structure, said concave spindle surface further having a consolidating area in the defined path of a high degree of coefficient of friction with respect to the consolidated yarn structure.
 3. An apparatus, as defined in claim 1, wherein said spindle is a freely rotatable spindle.
 4. An apparatus, as defined in claim 1, wherein said spindle is a driven spindle.
 5. An apparatus, as defined in claim 1, wherein said spindle includes suction means adapted to create a suction on the surface thereof.
 6. An apparatus, as defined in claim 1, wherein said spindle surface is electrically chargeable for attracting fibers.
 7. A method of consolidating a composite yarn structure to form a consolidated yarn structure comprising providing a source of a composite yarn structure, passing the composite yarn structure in contact with a spindle having a concave surface in which the composite yarn structure is passed through a defined path on the concave structure from an initial receiving area on the spindle surface to a discharge point thereon to thereby form a consolidated yarn structure, said composite yarn structure being brought into contact with a concave surface conforming to the equation y ekx wherein x is the axial distance from a point on the spindle axis; wHerein y is the circumference location from the axis from a given x value; and wherein k is a constant defining the curve of the surface and is smaller than
 0. 8. A method as defined in claim 7, wherein the source of composite yarn structure is passed for at least a portion of a convoluted path while in contact with the concave surface of said spindle which has a higher degree of coefficient of friction with respect to the composite structure and thereafter the yarn structure is passed through a further convoluted path in communication with the first-mentioned convoluted path while in contact with the concave surface of the spindle and which has a higher degree of coefficient of friction with respect to the resulting consolidated structure, the last-mentioned convoluted path having a diameter less than the diameter of the first-mentioned convoluted path, following which the resulting consolidated yarn structure is discharged from said last-mentioned convoluted path.
 9. A method, as defined in claim 7, wherein the passing of the yarn structure in engagement with the spindle drives the spindle.
 10. A method, as defined in claim 7, which includes the step of positively driving the spindle.
 11. A method, as defined in claim 7, wherein the yarn structure is subjected to a suction through at least a portion of said defined path.
 12. A method, as defined in claim 7, which includes the step of generating an electrical charge on the surface of said spindle.
 13. A method of consolidating a composite yarn structure to form a consolidated yarn structure comprising providing a source of a composite yarn structure, passing the composite yarn structure in contact with a spindle having a concave surface in which the composite yarn structure is passed through a defined path on the concave surface from an initial receiving area on the spindle surface to a discharge point thereon to thereby form a consolidated yarn structure, said composite yarn structure being brought into contact with a concave surface conforming to the equation: y ekx wherein x is the axial distance from a point on the central axis of the spindle defining a distance along the central axis from said point to one end of said axis; wherein y is the circumference location from any location on the central axis to the surface of said spindle for any given x value; and wherein K is a constant defining the curve of the surface and is smaller than
 0. 14. A consolidating apparatus comprising a rotatable spindle, said spindle having a surface configuration conforming to the general equation y ekx wherein x is the axial distance from a point on the central axis of the spindle defining a distance along the central axis from said point to one end of said axis; wherein y is the circumference location from the axis from any location on the central axis to the surface of said spindle on any given x value; and wherein k is a constant defining the curve and is smaller than
 0. 